MSAS is Japan's satellite-based augmentation system that improves the reliability and accuracy of GPS signals. It uses satellites and ground stations to correct errors in GPS positioning. MSAS provides horizontal guidance for aircraft from en route through non-precision approaches. It has met or exceeded requirements for accuracy, integrity, availability, and continuity since becoming operational in 2007. Future plans include supporting more precise approaches and transitioning to dual-frequency signals.

1. MSAS
MULTI-FUNCTIONAL SATELLITE AUGMENTATION SYSTEM

2. WHAT IS MSAS
 MTSAT Satellite Augmentation System (MSAS) is a
Japanese SBAS (Satellite Based Augmentation
System), i.e. a satellite navigation system which
supports differential GPS (DGPS) designed to
supplement the GPS system by reporting (then
improving) on the reliability and accuracy of those
signals.
 providing a service of horizontal guidance for En-
route through Non-Precision Approach.

3. The MTSAT Satellite Augmentation System (MSAS)
is the Japanese Satellite Based Augmentation
System (SBAS) System:[1] a GPS Augmentation
system with the goal of improving its accuracy,
integrity, and availability, and that uses the
Multifunctional Transport Satellites (MTSAT) owned
and operated by the Japanese Ministry of Land,
Infrastructure and Transport and the Japan
Meteorological Agency (JMA)
First tests were accomplished successfully, and
MSAS system for aviation use was declared
operational in September 27, 2007.

4. MSAS CONFIGURATION OVERAL

5. • 2 GEO, 2 MCS (Master Control Station), 4 GMS (Ground Monitor Station), and 2 MRS;
• MCS also has GMS function; MSAS has 6 domestic monitor stations.
• 2 MRS (Monitor and Ranging Station) for GEO positioning for GEO ranging function.
Ranging Signals
MTSAT-1RGPS Satellites
Ground
Network
Naha GMS
Fukuoka GMS
Tokyo
GMS
Sapporo
GMS
Hitachi-Ota MCS
(and GMS)
Kobe MCS
(and GMS)
Hawaii MRS
Australia MRS
Users
MTSAT-2
Augmentation Signals 6 GMS
in Japan
Canberra
MRS
Hawaii
MRS
MSAS Monitor Stations

6. MSAS Performances
MSAS for aviation use was commissioned on September 27, 2007.
MSAS provides service for air navigation with the following
characteristics
24 hours a day, 7 days a week.
Operational Information is provided as notice to airmen (NOTAM).
Use for En-route through Non Precision Approach (NPA) phase of flight,
horizontal guidance only.
Service over the Fukuoka Flight Information Region
SIGNAL STRUCTURE
Frequency : L1 = 1575.42 MHz
Bandwidth: L1 not equal to 2.2 MHz

7. Regional Air carriers
Fire Fighters
Government
MSAS APPLICATIONS

8. Contents
1. Accuracy
2. Integrity
3. Continuity
4. Availability

9. ACCURACY
Required: Less than 220 m (with SA on)
Observed value is less than 2,2 m

10. INTEGRITY
Required: less than 1 x 10^-7/hour
Faulty Tree Analysis leads 0.903 x 10^-7/hour

11. Availability
Required: more than 99.9%
Observed: 99.926%

12. Continuity
For the near future, there is a plan under development with the following priorities:
Support LPV-200 capability (additional GMS, software improvement).
Changes for transition to dual frequency SBAS (L1-L5) operations.
In order to meet continuity requirement, there must be
multiple GEO satellites otherwise some alternate
measure or mitigation of the requirement is needed